Truck auxiliary brake



J. V. POWELL TRUCK AUXILIARY BRAKE Sept. 30, 1952 Filed May 15, 1947 lllll" Ill III I III I l I Patented Sept. 30, 1952 UNITED STATES PATENT- OFFICE 2,612,241' TRUCK AUXILIARY BRAKE John V.Powell,Utah' v I Application May 15, 1947, Serial No. 748,194

. Regular truck brakes are-lined with material that is perfectly satisfactory on roads where running conditions are favorable, but are subject to being .burnt out on the heavier grades.

The prime object of the invention is to provide a simple, powerful auxiliary braking mechanism that .can be brought into operation to meet conditions that might prove ruinous to regular brakes. 1 l I It is also an important object to prevent undue Stresses on truck motors where these are used under compression, as is common practice, .to supply a part of the braking action.

During the course of the detailed description thatappears hereinafter, other objects of the invention will become self-evident. 1

Inthe accompanying drawing, which illustrates'one embodiment of the invention,

.Fig. '1; represents. a side elevation largely in vertical section taken on the line l-l in Fig. 2; 1 Fig. 2, a plan partially in horizontal section, taken on the line 2-2 in Fig. 1, parts in the foreground and parts in the background being omitted; I

Fig. 3, a fragmentary vertical section taken on the line 33 in Fig. 1; and,

Fig. 4, a fragmentary detail showing a modification. Referring to the drawing, the numeral H) denotes a spider-likerotor comprising a hub H from which radiate arms or blades l2. The hub I] l is rigidly secured, for example by means of 'a. key 13, on the usual drive shaft IA of a truck motor (not shown).

The arms [2 are rigidly secured in the hub ll either by being cast therein or welded in place, 'as'indicated at l5. 'tion of the usual crankshaft is clockwise, as indicated by the arrow in Fig. 1, the tip of each of the arms is preferably curved slightly away from the direction of rotation, as indicated at 16.

Encircling the spider ID at the periphery there- Considering that the rota-- 16 Claims. (crime-45 secured in a lug 18, while the half [1b is similarof is a brake shoe means or brake band I! that is' preferably made substantially in halves Ha Ha is welded or otherwise ly secured to a lug 19. The lugs 18 and I9 are hinged on a pin 20 so that the two halves Ila and 11b, relative to the spider 10, have limited opening and closing motions. In orderto effect the opening and closingmotionsof the shoes Ha and" [1b, these are pivotally connected at 2 l and 22 to the respectiverods 23 and 24. The rods 23 and 24 are disposed for back and forth movement, in this instance by means of pistons, one of whichis shown at-25, Fig. 1.. The pistons are reciprocatively mounted in the respective cylinders 26 and 21, the .cylindershaving the respective heads 28 and 29 that serve as guide for the respective rods. The cylinderszfi and?! have therespective integral lugs .130 that are pivotally connected at 3| to members 32 that advantageously are fixed-with respect to the truck chassis or framework (notshown). The spider to together with the shoes Ila. and

11b are enclosed in a casing having, a liquidtight lower portion 33 and an upper portion 34secured together along a parting plane 35. The lower portion 33 forms a reservoir for a liquid 36 such as oil, that at least partially submerges the spider and its shoes. v

In applying'the brake, air under pressure is admitted to the cylinders 26 and 21 whereby the respective pistons are moved forwardly and conseguently urge the respective contractile shoes Ha and I'll; againstthe tips I8 of the blades 12. This frictionally retards the rotation of the spider I0, and consequently slows the rotation of the drive shaft 14 accordingly. In order that the'fbraking force shall be properly. applied, the

pin'20 'is secured against displacement by being held in bearings 31, these bearings'being fixed, v

for-example by welding, on the casing 33. At the same time, in order to divide the braking substantially equally between the shoes Ila and 11b,

compressedair from a suitable source (not shown) is supplied to the two cylinders through conduits 38 that are controlled by a valve- (not shown) located within easy reach of 'theoperator of the truck. 7 Y. v V H Itis-to be noted that the cylinders 26 and 21, being pivotally -disposed at 3!, as already mentionedherein, are thus made to compensate for the slight oscillationv that results when'the respective piston'rods 23 and 24 are reciprocated. A feature of th invention is-that the brake is disposedto run in a bath of oil, indicated for example t 3E,the level of this bath beingcontrolled by means of a'pistc'n 39 that isreciprocatively mounted in a cylinder 40, the piston being actuated by means of a rod 4!. In Fig. 1 it will be noted that the piston 39 as shown, is near the end of its stroke towards the right, the oil bath 36 being approximately at its maximum depth. As dictated by the judgment of the operator, the level of the oil bath 34 may be lowered, or it may be completely evacuated from the casing 33, by moving the piston 39 towards the left. Thus, the cylinder .40, functions as a storage reservoir from which the oil may be selectively admitted to, or drained'from, the casing 33. For this purpose a pipe 42 provides communication between casing 33 and cylinder 40.

The piston rod 4| is reciprocated by any suitable well known means extending to a convenient point of manipulation by the operator. Since contractile brake shoe means disposed to frictionally engage the tips of said blades.

such means in numerous different'forms can'be;

readily supplied by any skilled engineer, it ,is deemed not necessary to illustrate a particular mechanism in this instance. v

The cylinder 40 may have a head 43 that serves as a guide for piston rod 4|. Arelief port i'sindicated at 44. j r Q In Fig.1, the brakeshoes are shown in the applied position, thatis to say, in the position occupied after compressed air has been admitted to the space 45. When the air is exhausted from this space in the respective cylinders 26 and 21, because of a manipulative act of the operator, compression springs, such as the one at 46, exert a tensioned force to retract the respectiverods -23 "and 24, together with their associated parts.

Each of the cylinders 26 and 21 has illustrated for example, at 47. I

The shaft [4 is rotatably mounted in bearings 48' which are suitably fixed on the framework a relief port,

"(not shown) of the truck, while the casing is fixed on members 49 that in turn ar also fixed on the said framework. I Y e y In operation, the blades l 2 of the'rotor l0 pass through the gap 50 betweenthe extremities of the respective brake shoes Ila and Nb, but are prevented from making undue noise by means of the curved tips I 6 that slide easily over the curved portion 5| of, for example, the shoe 11b.

A similar prevention of undue noise exists at the v-gap 52. In Fig. 4 is shown a construction of the rotor arms that bridges the gaps aforesaid, thereby keepingat least a portion of each spider arm constantly in contact with a brake shoe surface. In

this construction, ablade 53 has therounded pilot projection 54 that extends in the direction 'of.rotation, and a follower projectionif55. It, .Will be :noticed that the gap '50 in .Fig. 4 is completely lbridged. Boththe blades l2 and theblades53 are approximately radial inthe preferreddispois'ition thereof.

During operation of the brake the oil bath. 36 serves to prevent excessive heating of theblades and the brake bands, and also serves to retard excessive speed of rotation sincethe blades must splash through the'oil somewhatafter the per}- formance of a pump impe1le1'.; lt is desirable that the casing be made oil-tight,;which can: be

accomplished in any well known manner and need not be particularly illustrated in -the presentinstance- 1 1 1 1.1; 5.."

' It is desirable that the blades l21and' 5 3-. be made of material having considerable resiliency, for illustration,'spring steel or-heat-treated steel, so as to exert a certain degree'of yielding pressure against the brake shoes. -The brake shoes Fla and [lb are best made of a-tough steeljfor is intermittently drained.

4. A truck auxiliary brake according to claim 3, including means operative to selectively "circulate oil between said rotor blades, said blade tips and said reservoir. I r

5. A truck auxiliary brake comprising a rotor having a plurality of blades extending approximately radially thereof. to,'in effect, constitute a brake drum, said blades being provided with friction tips spaced apart circumferentially of the rotor free and independent of one another; a two-part contractile brake shoe means disposed to engage said'friction tips; and means operative to contract or to relax, 'as the case maybe, said brake shoe means; 1

6. A truck auxiliary brake comprisinga rotor having a plurality of'independent and spaced apart circumferential braking surfacemeans to, in effect, constitute a brake drum; contractile brake shoe means disposed to alternately engage said braking surface means and'to release the same; means operative to alternately contractand expand said contractile brake sh'oe means: and means disposed to'confinea liquid that at least partially submerges said plurality of independent and spaced apart circumferential-braking surface means and said'brake shoe means. 7

'7. A truck auxiliary brake according to claim 6, including means operative to selectively with draw the liquid from said plurality of independent circumferential braking surface means'or'to selectively restore the liquid thereto, as the. case maybe. :1: e

. 8. A truck auxiliary brake, comprisinga rotor having a plurality of spaced apart so as to be independent of one another circumferentiall'y disposed frictional brakin surface means to, in effect, constitute a brake drum; 'brakeshoe means operative to engage saidbraking surface means; and liquid submerging means operative selectively upon said frictional braking surface means and said brake shoe means. 5 1 9;. A truck "auxiliarybrake; comprising circumstitute a-brake drum, said blades having tip portions disposed to bridge said gap; and means 0p,-

.erative to; cause said" brake shoe means to, engage saidrotor. ,1 a 1: '10. A truck auxiliary brake accordingftoclaim 19. in lud m anso er ti e toi c i e apnly a bath of liquid to said brake shoe means and to said rotor, said means comprising a liquid-tight casing in which said brake-shoe means and said rotor are operatively disposed; a liquid storage reservoir and means operative to selectively transfer liquid from said casing to said storage reservoir, and vice versa.

11. Braking mechanism, comprising a rotor having a plurality of individually free blades extending approximately radially therefrom to, in effect, constitute a brake drum, said blades having respective arcuate friction tips spaced apart from one another and lying in the cylindrical surface of the brake drum; and contractile brake shoe means disposed to frictionally engage the said arcuate tips of said blades.

12. The combination recited in claim 11, wherein the friction tips project backwardly of the respective blades away from the direction of rotation of the rotor.

13. The combination recited in claim 11, wherein the friction tips project both forwardly and backwardly of the respective blades,

14. The combination recited in claim 11, wherein the blades are substantially elongated in planes which extend longitudinally with the rotative axis of said rotor, so that the axis of greater bending of each blade lies in the rotative plane of the rotor.

15. The combination recited in claim 11, where- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 606,959 Doolittle July 5, 1898 1,131,810 Zoller et a1 Mar. 16, 1915 1,192,233 Zevery July 25, 1916 1,193,366 Demara Aug. 1, 1916 1,781,437 Chisholm Nov. 11, 1930 2,391,074 Schnell Dec. 18, 1945 FOREIGN PATENTS Number Country Date 197,362 Germany Apr. 14, 1908 559,716 Germany Sept. 23,1932 

